Acrylic latex wood filler composition and method of making same

ABSTRACT

In broadest terms, a wood filler composition of the present invention comprises: from about 11.50 to about 17.50 weight percent water; from about 14.40 to about 21.60 weight percent ceramic microspheres; from about 2.48 to about 3.72 weight percent wood flour; from about 0.32 to about 0.48 weight percent thickener; from about 0.80 to about 1.20 weight percent glass bubbles; from about 12.24 to about 18.36 weight percent acrylic latex emulsion; and from about 36.06 to about 54.10 weight percent calcium carbonate. The composition preferably has a pH in the range of from about 8.4 to about 8.8. Further the composition preferably has a viscosity of 200,000 to 300,000 cps as measured on a BROOKFIELD RV viscometer (helipath on) with a T/E spindle at 20 rpm and 25° C.

TECHNICAL FIELD OF THE INVENTION

The present invention is directed towards wood filler compositions.Specifically, the present invention is directed towards acrylic latexwood filler compositions that are non-toxic and non-flammable, asdefined by the Federal Hazardous Substances Act.

BACKGROUND OF THE INVENTION

Presently there are a multitude of wood filler compositions in themarket. These wood filler compositions can generally be classified intoone of two categories. The first category comprises solvent-based woodfiller compositions. The second category comprises water-based woodfiller compositions.

Solvent-based wood filler compositions are not generally favored becausethey require the use of a solvent for clean-up. Further, solvent-basedwood filler compositions may be flammable due to the solvent. Thesolvent may also cause excessive shrinkage of the wood fillercomposition as it dries. Oftentimes, solvent-based wood fillers are notas durable as one would desire.

Water-based wood filler compositions are generally susceptible to attackby water. Additionally, it is oftentimes difficult for a water-basedwood filler composition to accept stain, thereby causing dissatisfactionwith the product.

SUMMARY OF THE INVENTION

The present invention overcomes many of the disadvantages of prior artsolventborne wood fillers. Wood fillers of the present invention arenon-flammable; exhibit minimal, if any, shinkage; offer improveddurability (i.e. no surface polishing) with a superior wood grainappearance; and accept stain better due to the presence of hardwoodfibers and microspheres.

Further, the present invention overcomes many disadvantages of prior artwaterborne wood fillers. Comparatively, wood fillers of the presentinvention offer better water resistance, improved stain acceptance (i.e.no over-staining), and improved durability (i.e. no stain loss afterweathering).

In broadest terms, a wood filler composition of the present inventioncomprises: from about 11.50 to about 17.50 weight percent water; fromabout 14.40 to about 21.60 weight percent ceramic microspheres; fromabout 2.48 to about 3.72 weight percent wood flour; from about 0.32 toabout 0.48 weight percent thickener; from about 0.80 to about 1.20weight percent glass bubbles; from about 12.24 to about 18.36 weightpercent acrylic latex emulsion; and from about 36.06 to about 54.10weight percent calcium carbonate. The composition preferably has a pH inthe range of from about 8.4 to about 8.8. Further the compositionpreferably has a viscosity of from about 200,000 to about 300,000 cps asmeasured on a BROOKFIELD RV viscometer (helipath on) with a T/E spindleat 20 rpm and 25° C.

While any suitable ceramic microspheres may be used in the presentinvention, it is preferred that the ceramic microspheres are G-3125Z-LIGHT SPHERES sold by 3M.

Further, any suitable wood flour (or combinations of wood flours) may beemployed, however, it is preferred that the wood flour is a 60-meshsized wood flour. It is more preferred that hardwood wood flour be usedin the present invention. A preferred wood flour for use with thepresent invention is maple wood flour in 60-mesh size as sold by LangFiber Products.

Additionally, a wide variety of thickeners may be used in the practiceof the present invention, however, it is preferred that the thickener isa methyl cellulose thickener, such as METHOCEL E-4-M sold by DowChemical.

Although many acrylic latex emulsions are suitable for use with thepresent invention, a preferred acrylic latex is RHOPLEX E-330, sold byRohm and Haas. RHOPLEX E-330 acrylic emulsion has a non-ionic charge,percent solids content of about 47%, and a pH of 9.5 to 10.0. A secondpreferred acrylic latex for use with the present invention is RHOPLEXAC-2235, also from Rohm and Haas. It is preferred that more than oneacrylic latex is used in the present invention. It is more preferredthat both RHOPLEX E-330 and RHOPLEX AC-2235 are used. It is mostpreferred that the RHOPLEX E-330 and RHOPLEX AC-2235 acrylic emulsionsare used in an approximately 2:1 ratio.

Although many calcium carbonates may be used with the present invention,a preferred calcium carbonate is #10 WHITE (GSP-40) available from ECCInternational. A second preferred calcium carbonate is OMYACARB 6 fromOmya Inc. It is preferred that more than one calcium carbonate is usedin the present invention. It is even more preferred that both #10 WHITE(GSP-40) and OMYACARB 6 are used. It is most preferred that the #10WHITE (GSP-40) and OMYACARB 6 calcium carbonates are used in anapproximately 2.6:1 ratio.

It is preferred that the wood filler composition of the presentinvention additionally comprises at least one biocide. Although afunctional amount of biocide should be used in the present invention, itis preferred that the biocide(s) constitute(s) from about 0.05 to about0.15 weight percent of the wood filler composition. It is most preferredthat the at least one biocide is ACTICIDE LA sold by Actichem.

It is further preferred that the wood filler composition of the presentinvention additionally comprises at least one surfactant. Although afunctional amount of surfactant(s) should be used in the presentinvention, it is preferred that the surfactant(s) constitute(s) fromabout 0.01 to about 0.80 weight percent of the wood filler composition.It is more preferred that the surfactant is TRITON X-405, sold by Rohmand Haas. The surfactant may be a non-ionic surfactant such as NOPCONXZ, sold by Henkel.

Additionally, it is preferred that the wood filler composition of thepresent invention comprises at least one stabilizer. It is preferredthat at least one stabilizer is a freeze-thaw stabilizer. A preferredfreeze-thaw stabilizer is propylene glycol. Although a functional amountof stabilizer(s) should be used in the present invention, it ispreferred that the stabilizer(s) constitute(s) from about 0.50 to about1.50 weight percent of the wood filler composition.

Wood filler compositions of the present invention may additionallycomprise at least one mildewcide. A preferred mildewcide is SKANE M8,sold by Rohm and Haas. Although a functional amount of mildewcide(s)should be used in the present invention, it is preferred that themildewcide(s) constitute from about 0.05 to about 0.15 weight percent ofthe wood filler composition.

Wood filler compositions of the present invention may additionallycomprise at least one colorant. The quantity of colorant(s) used willvary as a matter of choice and necessity. However, it is preferred thatthe colorant(s) constitute from about 0.01 to about 0.30 weight percentof the wood filler composition. If necessary, a pigment dispersant maybe required to ensure that the colorant(s) is dispersed throughout thewood filler composition. While a functional amount of pigment dispersantshould be used, it is preferred that the pigment dispersant constitutefrom about 0.01 to about 0.50 weight percent of the wood fillercomposition. For example, TINT-AYD WD-2509 Burnt Umber (available fromElementis Specialties) and AQUA YELLOW 597-49 (available from BordenChemical) may be used to impart a “natural” color to the wood fillercomposition. TAMOL 851, sold by Rohm and Haas, is a pigment dispersantthat not only disperses the colorants throughout the composition butalso helps to stabilize them as well.

A preferred method for preparing a wood filler composition of thepresent invention comprises the steps of: (a) providing a mixing vessel;(b) placing water, at least one biocide, at least one surfactant, and atleast one stabilizer in the mixing vessel under slow agitation; (c)mixing this combination of ingredients until substantially homogeneous;(d) adding at least one acrylic latex emulsion to the mixing vesselwhile agitating; (e) mixing the contents of the mixing vessel untilsubstantially homogeneous; (f) adding at least one ceramic microsphereand at least one wood flour to the mixing vessel while agitating; (g)mixing the contents of the mixing vessel until homogeneous; (h) addingat least one mildewcide to the mixing vessel while agitating; (i) mixingthe contents of the mixing vessel until substantially homogeneous; (j)adding water and at least one surfactant to the mixing vessel whileagitating; (k) mixing the contents of the mixing vessel untilsubstantially homogeneous; (l) adding at least one glass bubble to themixing vessel under slow agitation; (m) mixing the contents of themixing vessel under slow agitation until substantially homogeneous; and(n) adding water to the mixing vessel in sufficient quantity so as toproduce a wood filler composition having a viscosity of from about200,000 to about 300,000 cps and a pH of from about 8.4 to about 8.8.

The method may additionally comprise the step of adding at least onepigment dispersant. It is preferred that the step of adding the at leastone pigment dispersant is performed at the same time as the addition ofthe water, the at least one biocide, the at least one surfactant, andthe at least one stabilizer to the mixing vessel.

The method may additionally comprise the steps of (a) adding at leastone pigment to the mixing vessel; and (b) mixing the contents of themixing vessel until the at least one pigment is evenly dispersedthroughout. It is more preferred that these steps are performed prior tothe addition acrylic latex emulsions.

Finally, it is preferred that at least one of said at least onestabilizer is a freeze-thaw stabilizer.

In addition to the novel features and advantages mentioned above, otherobjects and advantages of the present invention will be readily apparentfrom the following description of the preferred embodiment(s).

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)

In accordance with the foregoing summary, the following presents adetailed description of the preferred embodiment of the invention thatis currently considered to be the best mode.

The present invention is directed towards a wood filler composition andmethod of making the wood filler composition. The wood fillercomposition of the present invention is particularly useful forrepairing damage to wood components.

A preferred composition of the present invention comprises, on a weightpercent basis:

Item No. Ingredients % by Weight 1 Water 11.00 2 ACTICIDE LA 0.10 3TRITON X-405 0.71 4 TAMOL 851 0.35 5 Propylene glycol 1.00 6 NOPCO NXZ0.03 7 TINT-AYD WD-2509 Burnt Umber 0.06 8 AQUA YELLOW 597-49 0.25 9Water 0.80 10 RHOPLEX E-330 10.35 11 RHOPLEX AC-2235 4.95 12 METHOCELE-4-M 0.40 13 #10 WHITE (GSP-40) 32.50 14 OMYACARB 6 12.58 15 SKANE M80.10 16 Glass Bubbles 1.00 17 Water 0.50 18 NOPCO NXZ 0.03 19 Water 2.1920 Maple Wood Flour - 60 mesh 3.10 21 G-3125 Z-LIGHT SPHERES 18.00TOTAL: 100.00

The above formulation has a pH of 8.4-8.8, total solids of 77.0-78.0%, aviscosity of 270,000 cps, natural color, and a weight per gallon ofabout 8.6 pounds.

The following describes a preferred methodology for compounding thepreferred wood filler composition described above, with reference to the“Item Nos.” used above:

Place items 1, 2, 3, 4, 5, and 6 into a clean mixing vessel under slowagitation. Blend until the mixture is homogeneous. Next, add items 7, 8,and 9 to the mixing vessel under agitation and mix until the colorpigments are evenly dispersed. Next, add items 10 and 11 to the mixingvessel under agitation and mix until mixture is homogeneous. Next, additems 12, 13 and 14 to the mixing vessel under agitation and mix untilhomogeneous. Then add items 20 and 21 to the mixing vessel underagitation and continue mixing until the mixture is homogeneous. Next,item 15 is added to the vessel and mixed into the batch. Then items 17and 18 are added to the mixing vessel and mixed evenly into batch. Item16 is added to the mixing vessel under slow agitation and mixed untilmixture is homogeneous. Finally, item 19 is added in increments toachieve desired viscosity, weight per gallon, and pH levels.

Surfaces to which the wood filler of the present invention is to beapplied should be clean, dry and free of grease, oil and looseparticles. The surface and the wood filler should be at a temperature of40° F. or warmer. Application of the wood filler should be generous andexcess can be removed with a putty knife but some extra wood fillershould remain to allow for flush sanding after drying. For normalrepairs, one application usually suffices although for deeper cracks,two or more applications are better than one heavy one. The wood fillermust dry between applications. Shallow repairs can be sanded after 15minutes of application but deep repairs require 1 to 8 hours. Avoid highspeed sanding. If a machine sander is used, use on-off-on-off action.Desired finish may be applied after sanding, one hour being allowed fordrying of water-based paint and overnight for oil-based paint, shellacor varnish. Stain should be applied within 1 hour after sanding.Staining requires medium to coarse sanding for best results. Iffine-sanded, stain will need more time for penetration. For true colormatch, test wood scrap to determine proper stain color and time for bothfiller and wood. After finishing a job, tools and hands can be washedwith water before wood filler dries.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiments,it is to be understood that the invention is not to be limited to thedisclosed embodiment(s), but on the contrary, is intended to covervarious modifications and equivalent arrangements included within thespirit and scope of the appended, claims, which are incorporated hereinby reference.

1. A wood filler composition, said composition comprising: from about11.50 to about 17.50 weight percent water; from about 14.40 to about21.60 weight percent ceramic microspheres; from about 2.48 to about 3.72weight percent wood flour; from about 0.32 to about 0.48 weight percentthickener; from about 0.80 to about 1.20 weight percent glass bubbles;from about 12.24 to about 18.36 weight percent acrylic latex emulsioncontaining about 46 to about 48 weight percent solids; and from about36.06 to about 54.10 weight percent calcium carbonate, wherein saidcomposition has a pH in the range of from about 8.4 to about 8.8, saidcomposition having a viscosity of from about 200,000 to about 300,000cps.
 2. The wood filler composition according to claim 1 wherein saidwood flour is a 60-mesh sized wood flour.
 3. The wood filler compositionaccording to claim 1 wherein said thickener is a methyl cellulosethickener.
 4. The wood filler composition according to claim 1 furthercomprising at least one biocide.
 5. The wood filler compositionaccording to claim 1 further comprising at least one surfactant.
 6. Thewood filler composition according to claim 1 further comprising at leastone stabilizer.
 7. The wood filler composition according to claim 6wherein said at least one stabilizer comprises a freeze-thaw stabilizer.8. The wood filler composition according to claim 1 further comprisingat least one mildewcide.
 9. The wood filler composition according toclaim 1 further comprising at least one pigment dispersant.
 10. The woodfiller composition according to claim 8 further comprising at least onecolorant.
 11. A method for preparing the wood filler composition ofclaim 1, said method comprising the steps of: providing a mixing vessel;placing water, at least one biocide, at least one surfactant, and atleast one stabilizer in said mixing vessel under slow agitation; mixinguntil substantially homogeneous; adding at least one acrylic latexemulsion to said mixing vessel while agitating; mixing untilsubstantially homogeneous; adding at least one ceramic microsphere andat least one wood flour to said mixing vessel while agitating; mixinguntil homogeneous; adding at least one mildewcide to said mixing vesselwhile agitating; mixing until substantially homogeneous; adding waterand at least one surfactant to said mixing vessel while agitating;mixing until substantially homogeneous; adding at least one glass bubbleto said mixing vessel under slow agitation; mixing until substantiallyhomogeneous; and adding water to said mixing vessel in sufficientquantity so as to produce a wood filler composition having a viscosityof from about 200,000 to about 300,000 cps and a pH of from about 8.4 toabout 8.8.
 12. The method according to claim 11 additionally comprisingthe step of: adding at least one pigment dispersant to said mixingvessel.
 13. The method according to claim 11 additionally comprising thesteps of: adding at least one pigment to said mixing vessel; and mixinguntil said at least one pigment is evenly dispersed.
 14. The methodaccording to claim 11 wherein at least one of said at least onestabilizer is a freeze-thaw stabilizer.